Demonology with Professor Rin and Yukio
by Daygon Yuuki
Summary: It was all Mephisto's fault they were stuck in this world. Combating demons easy. Teaching children? Not so much, especially if they were the in training wizards. Now if only her brothers would leave her alone and let her teach in peace, she was a thousand years old demon not a damsel in disaster. Fem Rin
1. Chapter 1

**Summary: It was all Mephisto's fault they were stuck in this world. Combating demons easy. Teaching children? Not so much, especially if they were the in training wizards. Now if only her brothers would leave her alone and let her teach in peace, she was a thousand years old demon not a damsel in disaster.**

 **Disclaimer: If you recognise it I don't own it.**

Rin blamed Mephisto for all this. Rin was stuck here, in this castle like place which practiced magic. Oh, how she longed to be at home and in her soft and comfortable bed but noooo, Mephisto had to take this job and she had to be put up to it.

So here she was, agreeing to teach a bunch of brats about demons. She really did want to go home but a deal was a deal. If only that clown was not her brother.

"Ah, miss Rin. Welcome to Hogwarts. I take it Sir Phelis send you?"

Nah, a troll send her, of course it was Mephisto who had send her. It was not like anyone could force her now that she had learned to control her flames but with her brothers being over protective you never know. They had not even allowed her to date, except Egyn.

"Yes, may I inquire what was it you needed my assistance for?"

She was not native, as she might have been in the past. Apparently, thousands of years did teach you a great deal about something and one of the things she had learned was that Mephisto always had an utter motive behind everything he did.

"Ah, you see we have a nut case of a wizard called Lord Voldamort who had made himself immortal by splitting his soul and according to a prophesy only Harry Potter could kill him?"

She had heard the whole story from an amused Samael who was snickering the whole time. He obviously found it quote funny.

"Yes, my brother did give me the short version"

She did not want to spend more time than she had to here. A spa was waiting for her when she went back, curtsey of Egyn, bless him

"I want you to keep an eye on him, Harry Potter I mean. He'll be starting the school this year"

Now she was reduced to being a babysitter. Not only she had to teach but also keep an eye on a brat.

Not her forte. They should have gotten Yukio to do it. He was expert in these things not her.

"I'm not sure I'll be able to do it"

Being honest was the best deal. Fuck Mephisto, she was not doing it. It was not her ideal plan to spend a year in school filled with children at all.

"But I'm afraid we've already had a deal and a demon never backs away on his words right?"

She might be a half-demon but still a demon and no matter how much she hated it rules were rules. She had to comply.

"Fine. We have a deal. But I'm bringing Yukio along"

She was not gonna hear a word more on this. If she had to suffer she would make her twin suffer too. Her twin who would actually manage to pass as a teacher looking 22, while she looked 16.

Damn her youthful face.

 **This is a trail chapter. If this gets response I'll update otherwise I'll not.**


	2. Chapter 2

**And I'm officially continuing this. Hope you all like this as much as you like my other stories. I'll actually like some feedback.**

 **That means I'm asking you to review.**

 **Summary: It was all Mephisto's fault they were stuck in this world. Combating demons easy. Teaching children? Not so much, especially if they were the in training wizards. Now if only her brothers would leave her alone and let her teach in peace, she was a thousand years old demon not a damsel in disaster.**

 **Disclaimer: If you recognise it I don't own it.**

"Yukio, we have a problem"

If she was gonna do it then Yukio was too. Besides Yukio had actual experience in this kind of things, being a cram school teacher and all. She had zero experience.

"What did you do now nee-san?"

Her twin question stung her. Not every problem was because if her. True demons chased them because either they wanted to mate Satan's only daughter or she had offended them. Ok, she did break a lot when fighting. Ok, she did cause a lot of verbal spats, and she would stop right there.

But her point stood, it was not her fault as whole. It was Mephisto's.

"Oi, not ever problem is caused by me. This one is Mephisto's. He signed us up to teach about demons at a magic school"

Really, this was all of his clown like brother's fault. _He_ was the one to sign a deal.

"You mean he signed you up to teach and you decided that since I had experience I'll be the perfect specimen to help you"

Well, she'll not call him a specimen but then again this was exactly what she had thought.

"Yuki, help me my precious"

Here she was being melodramatic, hugging and squeezing her brother but if it got Yukio to cooperate then she was not complaining.

"OK sis. I'll help you. Now get off me"

Yup, really not complaining at all.

 **...**

The castle was really big for human standards but being a demon for so long Rin had seen bigger. She was not really interested in the castle but the forest was clearly a different matter. It was full of demonic energy.

"Rin, let's go. We're late for the sorting ceremony"

She was really not interested in the sorting. She wanted to run in the forest and let herself loose nut noooo, she had to look after some magical brats.

Following her brother she entered the castle. A man with greasy hairs and really awful smell greeted them. She really did not like him, mainly because he smelled so bad but he was not bad looking, just a little too old for her perhaps.

"I'm Severus Snape, the potion master. I've been asked to accompany you inside"

She'll let Yukio do all the talking. She really was not one to socialise with such a crowd. It was more Yukio's thing.

"I'll take this opportunity to welcome our new Demonology professors. Welcome Professor Rin and Yukio Okumura. Don't go on their ages there's quite experienced -"

Young? She was easily old enough to be their grandmother's grandmother, she just did not look like it. She felt a lot of eyes on her. Someone whistled at her and that was not such a good idea at his part because next thing she knew Yukio had fired a warning shot which just breezed past the boy. Man, what had gotten into Yukio, in all her brother's actually. Whenever an boy approached her they would go all crazy.

"Professor Okumura, please don't shoot any students if you can help it. They are important for us all"

Maybe she should talk to Yukio, but last time she had done it it had not gone well at all so maybe she should not.

"Sorry, my hand slipped"

Yeah, hand slipped her ass. It was deliberate on his part. And then the ghosts came out and Yukio fired some more shots at them.

"Professor Okumura"

"Slipped again"

Yeah, she really would get that one on one chat with Yukio.

 **And I've decided to continue this. But they will be more like snaps of chapters.**


	3. Chapter 3

**Yes, I'm updating. You're not dreaming. At least I didn't leave it for years like some people. No offence to anyone.**

 **Summary: It was all Mephisto's fault they were stuck in this world. Combating demons easy. Teaching children? Not so much, especially if they were the in training wizards. Now if only her brothers would leave her alone and let her teach in peace, she was a thousand years old demon not a damsel in disaster.**

 **Disclaimer: If you recognise it I don't own it.**

Yukio was an expert at teaching brats. He had been a teacher of True Cross for years. He even had _Rin_ as a student when she was young. If he could take on Rin then Hogwarts was a piece of cake.

Currently he was busy making lesson plans. First lesson of being a teacher was to have a lesson plan to follow. It was really important to know what to teach which year or things could turn up a mess. Another was to always have a back up plan. Well, for small kids it was but if this batch had any trouble magnet like his sister, well let's just say prevention was better than cure.

They had rested Yukio's patience as it was, next time he was not gonna miss.

 _Bam_

The door opened and Rin entered. She had been bored the whole time here and it had only been three hours.

"Yuki, I'm bored. As in really really utterly bored. Play with me"

By now she was hanging on to him and least to say it was a very suggestive position. Damn his brain for interpreting things like this.

"Nee-san, let me go. Take a walk around Hogwarts for all I care but let me go. And take the stick with you too"

He did nit care what he had to do. He just wanted her to stop hanging up onto his arm. Luckily for him she did.

Five minutes later he remembered that his sister had left without any form of protection. True she could use her flames but she was prohibited from using them since last time she had done so.

Now he had to go after her. Things were not looking good for him. Not good at all.

 **...**

Rin did like this school even if it was boring. At least it was huge and with a lot of hidden passages. She had even caught some kids out, mostly boys who were checking her out. Ah, it was good to be young. Or at least appear to be.

Right now she was walking up the stairs but to much to her surprise they shifted suddenly.

Automatic floor changing stairs? She'll have to get Mephisto to install some in True Cross.

For now she decided to go where the stairs were leading her.

"Prof, care to join us for a bit? You seem cool"

A redhead boy called out to her. Screw exploring. That boy looked to be fun type. So she hurried down the stairs. The redhead boy had another boy besides her who looked like him.

Twins?

How fun.

"Prof, I'm Fred and he's George"

The one called out to her. They did have difference in their life force but not too much.

"No, I'm Gred and he's Forge"

The other one called out. A laugh escaped her. They were pretty amusing.

"Well boys, you should go back to your dorm or I'll have to deduct points"

She meant that in a friendly way and by the grin on the twin's faces even they knew it

Suddenly something brushed past her and for a fleeting second she thought it was her tail but then remembered that it could not be so. Her tail was hidden.

It happened again startling her and in her fright she let loose her flames a little. The twins snickered at her or at the object she had burned.

It was black cat who seemed to be glaring at her. Fur was burnt at certain places and she seemed to be a funny site. Suddenly the cat took off into a run.

"Damn Prof, to have an accidental magic explosion at your age? By the way how old are you sixteen?"

One who had introduced himself as Fred said. She let out a short but thanked God in her head. They had thought it to be a magic explosion.

"It's rude to ask a lady for her age. But just for reference I'm turning 19 this year"

The twins snickered again. She rolled her eyes at them. Immature human kids, how she was one of them herself long ago.

"One thousand and nineteen. Well I gotta go. Bye boys"

And she left two gaping boys behind. Should she inform Yukio of this? Nah, she'll let him be. He did not need any more grey hairs than he already had.

"One thousand and nineteen? She had to be lying"

Poor unsuspected human boys.

 **Hopefully it was good for you. Any guess whom the cat was?**

 **Kindly review.**


	4. Chapter 4

**I'm** **late but I have an excuse. My finals started and I somehow got into Kuroko no Basuke again. But just so you don't feel abandoned here is the next chapter.**

 **Disclaimer: Nah, I don't own it. Never will.**

Morning was a time Rin hated. You hard bed hairs and you had to leave your comfortable bed and get out. And now she had another reason to hate the mornings.

She had a class of brats to teach.

Good thing Yukio was with her. He knew how to pacify her. Too bad for him he became the object of her bitching.

But once she woke up for real and explored around it was alright.

The breakfast had a wide variety of items, and she loved it. But right now she found herself being watched.

Well being a sixteen years old looking teacher it had to be excepted but that was not why she was being looked at right now for and it was not a student who was looking at her.

No, it was Professor Minerva McGonagall. She was looking quite funny with her hat covering her whole head and she could feel a light magical aura around her as if she was hiding something. And the glare coming her way was too intense. Just what had she done wrong anyway? It's not like she had burned off her hairs. She did that to that black haired cat. Was she her cat or something?

"Do you know what is wrong with McGonagall. She's giving me quite the evil glare"

She asked the black haired to her right. She heated his odour but he might give her good information.

"Apparently someone burned off her hairs when she was in her cat form so she's in a bad mood. I really want to meet who did it"

Oh, oh. She had not burned off her cat's hairs. Rin Okumura had burned off Minerva McGonagall's hairs.

 **...**

Yukio hated children with a passion.

Sure he had taught children before but that was a different case. Most of them were over sixteen and knew what was goof for you and what was not.

This was an eleven year's old kid's class. They were all noisy and way too loud for his own good. These were the Gryffindor first year class. The headmaster had told him that Harry Potter was in this year and he had heard about him.

But the point remained that they were all too loud and annoying and he had till now caught too many of them passing notes. Some of those containing his sister. He had already fired too many warning shots, meaning his hand was slipping a lot. Next time his hand slipped someone was gonna get hit in the head. He'll not miss from here. Besides they were all stupid and childish. He ignored the part of his brain that said that they were children.

"Can someone tell me what a hobgoblin is? Yes Granger-san"

At least not all of them were hopeless. This girl knew her stuff. The door opened with a poop and entered Rin with a horde of hobgoblin.

"Yukio, I've brought some of these guys for practical demonstration"

And the hoard flew in from the door.

All hell broke loose. The hoard of children started screaming and running out the door. Rin quickly took care of the ones going after children and he shot the rest. At this rate both his bullets and blood pressure would go out the rooftop.

He already had one child in Rin who he had to take care of. He could not possibly take care of half a school. He'll go mental.

Well he had to go to shop for more bullets, he'll get his head checked out too. Just in case.

 **Done. Read and don't forget to review.**


	5. Chapter 5

**I should have posted this a lot earlier but exams held me back and then I begun reading Black Haze. It had seriously good characters.**

 **Disclaimer: Don't own it**

"So you say you're having trouble concentrating, having urge to shoot people and oh mood swings? Am I right Okumura-san?"

Yukio had finally decided to have the brain check and to say he was glad would be an underestimation. He had heard a lot about doctor Poppy Pomfey. She was one of the best. So it was safe to talk to her.

"That's right doctor"

So far she had asked him to list all that he thought was wrong with her. So he had. All his irritation and his urges he had blurted out at her.

"And all that over your sister?"

This was by far her eighteenth question and sixth time repeating all this. Just what was wrong with her? Did she not get it on her first try.

"I'm not sure this is leading to somewhere"

Yukio wa more that sure she was just humouring him and that she had already drawn her conclusion. He so did not like where this was heading.

"I'm assuring you Mr Okumura, it's not something big. It happens to everyone. You've been together and alone and it's common for a man to feel this way about a woman."

He was right. She completely misunderstood. He had to correct this and now.

"I assure you I'm not in love with my sister. We have a completely platonic situation"

He assured. The woman's eyebrows rose up.

"I never said you were Mr Okumura. I was suggesting you feel possessive of her as a brother. But form your outburst I'm thinking something different. Anyway she's a fully grown woman so you don't need to worry so much about her"

Yeah right. She had not met Rin yet had she? She was trouble personified.

"Yukiiiiiii, look what I found, this poor puppy was lost in the woods"

Rin entered the scene with a small puppy, no a wolf cub in her arms. The pup was completely docile till she handed it to Yukio. Then the pup turned into a wild animal, scratching and biting.

"Isn't it a darling cutie. Can we keep Izel?"

She had even named it? Now Poppy can see why Okumura had been so worried. Did his sister pick up strays, especially ones which made an attempt on his life.

She took in the scene of one wolf pup attacking a fully grown man with his sister smiling angelically in the background.

She pitied Mr Okumura.

 **...**

"Now class, we're having someone join us. Please welcome Professor Okumura who would be supervising us."

Hagrid introduced to his first years the smiling professor who have them all a wave in greeting. Her other hand holding onto the wolf cub she had found.

"Professor, is that a wolf cub? Isn't it dangerous?"

Hermione asked, a little afraid to question her teacher. The addressed person ignored the girl fully, too engrossed in the pup.

"What do we have here Mrs Okumura. Is that a Teresina Wolf cub? L-Let it go Mrs Okumura or the whole pack would come in search of it. How long have you been carrying it again?"

Hagrid asked. The children near had heard him took a step back in fright. Rin didn't know what the big deal was. This was just a pup.

"The whole while. I found him in the morning"

Now that he thought, the cub's family would be worried about it. Maybe she should let it go. But it was so cute and cuddly she could just not.

A growl came from behind the bushes and suddenly wolf emerged into the clearing, growling.

Children begun to run around and Hagrid asking her to release the pup. So did do a bummer, there goes her puppy.

Then something else caught her eyes. It was a hamster, a green hamster. How cute and so she picked up the hamster and tool it with her.

Poor Yukio when returned to the room found some of his things missing and a note by one of his elder brothers. Schools students accounted for a demon king causing havoc among the halls of Hogwarts before he was banished for the time being by the headmaster and Rin Okumura.

Everyone knew how Amaimon got in though and how he got Yukio Okumura's gun, but of course no one had proof and this no one testified. It became one of the seven mysteries of Hogwarts.

 **That's it. Read and review.**


End file.
